Process of vulcanization.



'PATBNTED AUG. 11, l903 W. H. ROBERTS. PROCESS OF VULGANIZATON.

-.APPLIU'ATIOI FILED DEO. 8. 1902.

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' citizen of the ne. 736,336. i "UNITED 'Srnrns WALTERH. nonnnrs; or

`Paocess or uuLon sPEcIFIcATIoN forming pareqf Letters Patent ne'.

AIDlication filed December 8, 1902.

Be it known that I, WALTER II. ROBERTS, a United States, residing at Portland, in the county of-Cumberland and State of Maine, have invented certain new and use- Ai'ul Improvements in Processes of Vulcaniza tion and I do hereby declare the following to be a full, clear, invention, such in the art to wh use the same.

My invention relates to anew discovery in and exact description of the as will enable others. skilled '/ch it appertains to make and `vulcanlzing india-rubber in Which a greater Sametime applying preparation; and it consists, broadly, in cooking the same in a closed receptacle and at the a current of electricity thereto. i

In order to graphically demonstrate the Working of my new process I have illustrated i the same in the accompanying drawings, in

i and iiask, and Fig.

)of the usual Scially by dentists lin the vulcanization of rub- Ia strip or cylinder Il of in contact with the bottom ol the coppcrvcssel,

` thereof. w As Figure l is a sectional view of a vulcanizer 2 is a top plan view oi.' the lining and cover.

Saidl vulcanizer consists of a copper shell 'A form and description used espeber for use in the making of dental plates or dentures. I insert within said Acopper vessel zinc, said zinc. being but not necessarily in contact with the sides is always used in processes of this kind, especially when it is desired to make artificialdentures, I use a flask C, so called,

1 and packed in very closely `iiask is of sufficient size to be in contact with @tom of the copper made of iron or any other suitable metal. In

"it is placed the teeth in the desired position, the

spaces between said teeth being filled in with small pieces of dental rubber, so called, and tightly.` The the zinc and at the same time rests on the botvessel. I sometimes place in the bottom of the vessel a small quantity of water, although this is not absol ntely necessary for the successful Working of thi sproccss. I also insert in the copper. vessel and over the zinc lining a cover D of zinc, saidpcover having a small vent F in the top thereof. I then j screwdown the topE of tl 1e copper receptacle tightly, so as netto allow the escape oi' any air rent is directed from Patented August 11,1903.

PORTLAND, MAINE.

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736,336, dated August 11, 1903.. Serial No. 134,226. (No specimens.)

vessel` and the temperature therein is grad` ually raised to 320o Fahrenheit. By the introduction of the Zinc into the copper vessel a com plete voltaic battery is formed. The iron flask, placed, as it is, so as to be in contact both with the copper vessel and the zinc, forms a conductor for the current generated. This current is carried b the flask to the rubber of which the denture is composed. The heat applied to the copper vessel both accelerates and intensifies this,A electric action, the flask itself serving as the means whereby the curits source to the rubber denture Within. The electric current thus generated and thus conducted tothe denture serves as a means for aiding the action of the heat upon the dental rubber, .the electric current oi' itself carrying no heat to the denture, but acts on the rubber in s'ueh a way that the hydrogen is more readily released from the mass. The hydrogencan be and has been in former processes released by the action of heat alone; but the presence of the electric current hastens the action because by its action on the -dental ru bber the hydrogen atoms are released more quickly. The time thus saved in cooking by conducting a quantity of electricity to the rubber is from thirty to forty-five minutes.

`In the previous process of vulcanizing a copper vessel has been used and an iron flask placed in the bottom thereof. The contents of the ilask have been prepared in the same Way as in my device. lVater is placed in the bottom of the. copper vessel and the cover screwed down tight,so as to prevent the escape of any steam. Heat is applied and the te1nperature, as indicated by a suitable thermometer, is brought to 320O Fahrenheit and there maintained for from iifty to sixty minutes before the india-rubber is suii'ieientl r vulcanized to maintain the proper rigidity and elasticity, taking in all a period of an hour and a quarter to an hour and a half.

B y using my improved method, especially in cooking dentures of the usual thickness,| it

is only necessary to bring the heat in the copvv per vessel to 320 Fahrenheit and there maintain it for a short time it beinfr onl f -neceso 5 sary to keep the flask within the copper vessel a time not exceedir. thirty minutes from the time that the heat i; first applied. In

` orsteam. .Heat is then applied to the copper 1 ico ' scribedinthis specification,

ucooking dentures "of unusual thicknessnit is'f not necessary tobri'ng the heat inthe copperv Fahrenheit; but in the.'

` 'fplacing {fesselto above 2805 .cooking of both these 'forms of ,dentures vthe tineis venyfznaterially lessened a' 'd i'n'fmost easeseduee'flfhearly one-half. f I do'not Wshto limit myself tothe'exact manner of generatingy .the electricity as is-de- 'forthe sende may be `applied from the outsideby means of suit.- able conductors running inthe' bottom ofthe coppe-r Vessel and `.being,brought in contact With theask, it being necessary only. that when the'r'ubber is beingv y lcanized the same I 5l be done -ifn thep'reseneeof 'an electric current.

What'Iclaim as' mysinvention, angl desire -iwsecuribyLettepsratent, isf

i. YThe f process of vulcanizing rubber which cons'stsin'yeooking itric'current.

he same in an-'air-tight vvessel sind conveying to' seid@rubber'nteiec-.j c

' 2. JThe process the samein v a i of iv'ulcanin-ingl closed vessel fliayng;

Wetter in the bottom thereof, heating the'weter..

tosaid rubber an electric current.' v

to a v'ulcan'iz'ing te'mperatnreand conveying 3. `The process lof Vulcanizin g rubber whichV consistsin cooking the same in an air-tightvessel at ahi-gh temperature and. conveying.

to said rubber during 'said cooking' an elec- 'g tric current.

, In testimony ELGINA C. VERRILL.

ulfhereof have fixedmy sig- I nature, in presence ofwtvowitnesseshis28th 

